Chapter: Views of Earth Table of Contents Section 3: MapsMaps Section 1: Landforms Section 2: ViewpointsViewpoints

The three basic types of landforms are plains, plateaus, and mountains. Plains Landforms 1 1

Plains are large, flat areas, often found in the interior regions of continents. Plains Landforms 1 1 Plains often have thick, fertile soils and abundant, grassy meadows suitable for grazing animals.

Plains Landforms 1 1 Plains also are home to a variety of wildlife, including foxes, ground squirrels, and snakes. When plains are found near the ocean, they’re called coastal plains.

A coastal plain is often called a lowland because it is lower in elevation, or distance above sea level, than the land around it. Coastal Plains Landforms 1 1

The Atlantic Coastal Plain is a good example of this type of landform. Coastal Plains Landforms 1 1 This area has low rolling hills, swamps, and marshes.

Coastal Plains Landforms 1 1

The Atlantic Coastal Plain began forming about 70 million years ago as sediment began accumulating on the ocean floor. Coastal Plains Landforms 1 1 Sea level eventually dropped, and the seafloor was exposed. As a result, the coastal plain was born.

The central portion of the United States is comprised largely of interior plains. Interior Plains Landforms 1 1 A large part of the interior plains is known as the Great Plains. It is a flat, grassy, dry area with few trees. The Great Plains consist of nearly horizontal layers of sedimentary rocks.

Plateaus are flat, raised areas of land made up of nearly horizontal rocks that have been uplifted by forces within Earth. Plateaus Landforms 1 1 They are different from plains in that their edges rise steeply from the land around them.

The world’s highest mountain peak is Mount Everest in the Himalaya—more than 8,800 m above sea level. Mountains Landforms 1 1 The four main types of mountains are folded, unwrapped, fault- blocked, and volcanic.

The Appalachian Mountains and the Rocky Mountains in Canada are comprised of folded rock layers. Folded Mountains Landforms 1 1 In folded mountains, the rock layers are folded like a rug that has been pushed up against a wall.

Folded Mountains Landforms 1 1 To form folded mountains, tremendous forces inside Earth squeeze horizontal rock layers, causing them to fold.

The southern Rocky Mountains in Colorado and New Mexico are unwarped mountains. Unwarped Mountains Landforms 1 1 High peaks and sharp ridges are common to this type of mountain.

Unwarped Mountains Landforms 1 1 Unwarped mountains form when blocks of Earth’s crust are pushed up by forces inside Earth.

Fault-Block Mountains Landforms 1 1 Fault-block mountains are made of huge, tilted blocks of rock that are separated from surrounding rock by faults.

These faults are large fractures in rock along which mostly vertical movement has occurred. Fault-Block Mountains Landforms 1 1 When these mountains formed, one block was pushed up, while the adjacent block dropped down. This mountain-building process produces majestic peaks and steep slopes.

Volcanic Mountains Landforms 1 1 The deposited materials pile up, layer upon layer, until a cone-shaped structure forms. Volcanic mountains begin to form when molten material reaches the surface through a weak area of the crust.

Section Check 1 1 Question 1 ________ are flat, raised areas of land with horizontal rocks that were uplifted. A. Coastal plains B. Interior plains C. Mountains D. Plateaus NC: 5.01, 5.03

1 1 Section Check Answer The answer is D. Plateaus are found at higher elevations than plains. NC: 5.01, 5.03

Section Check 1 1 Question 2 When molten material reaches Earth’s surface through a weak area, _______ mountains begin to form. A. fault-block B. folded C. upwarped D. volcanic NC: 5.01, 5.03

1 1 Section Check Answer The answer is D. Mount St. Helens and Mount Shasta are volcanic mountains. NC: 5.01, 5.03

Section Check 1 1 Question 3 Describe the difference between the formation of folded mountains and fault-block mountains. NC: 5.01, 5.03

1 1 Section Check Answer Folded mountains form when rock layers are squeezed from opposite sides. NC: 5.01, 5.03

1 1 Section Check Answer Fault-block mountains form when some rock blocks move up along a fracture and an adjacent block moves down. NC: 5.01, 5.03

Latitude and Longitude—Latitude The equator is an imaginary line around Earth exactly halfway between the north and south poles. Lines running parallel to the equator are called lines of latitude, or parallels. Latitude is the distance, measured in degrees, either north or south of the equator. Viewpoints 2 2

Latitude and Longitude—Latitude The equator is at 0° latitude, and the poles are each at 90° latitude. Locations north and south of the equator are referred to by degrees north latitude and degrees south latitude, respectively. Viewpoints 2 2

Longitude The vertical lines have two names—meridians and lines of longitude. Just as the equator is used as a reference point for lines of latitude, there’s a reference point for lines of longitude—the prime meridian. Viewpoints 2 2 This imaginary line represents 0° longitude.

Longitude Longitude refers to distances in degrees east or west of the prime meridian. Viewpoints 2 2 Points west of the prime meridian have west longitude measured from 0° to 180°, and points east of the prime meridian have east longitude, measured similarly.

Prime Meridian The prime meridian does not circle Earth as the equator does. Viewpoints 2 2 Rather, it runs from the north pole through Greenwich, England, to the south pole. The line of longitude on the opposite side of Earth from the prime meridian is the 180° meridian.

Prime Meridian You can locate places accurately using latitude and longitude. Viewpoints 2 2 Note that latitude position always comes first when a location is given.

Time Zones Time is measured by tracking Earth’s movement in relation to the Sun. Viewpoints 2 2 Each day has 24 h, so Earth is divided into 24 time zones. Each time zone is about 15° of longitude wide.

Calendar Dates In each time zone, one day ends and the next begins at midnight. Viewpoints 2 2 If it is 11:59 P.M. Tuesday, then 2 min later it will be 12:01 A.M. Wednesday in that particular time zone.

International Date Line You gain or lose time when you enter a new time zone. Viewpoints 2 2 The International Date Line is the transition line for calendar days.

International Date Line Viewpoints 2 2 If you were traveling west across the International Date Line, located near the 180° meridian, you would move your calendar forward one day. Traveling east, you would move your calendar back one day.

Section Check 2 2 Question 1 The imaginary line representing 0º longitude is the ________. A. equator B. International Date Line C. prime meridian D. time zone transition line

Section Check 2 2 Answer The answer is C. The prime meridian runs from the north pole to the south pole through Greenwich, England.

Section Check 2 2 Question 2 What imaginary line separates Earth into the northern and southern hemispheres? A. equator B. International Date Line C. prime meridian D. time zone transition line

Section Check 2 2 Answer The answer is A. The equator is at 0º latitude, and the poles are each at 90º latitude.

Section Check 2 2 Question 3 What location is nearest to the transition line for calendar days? A. 0º latitude B. 0º longitude C. 180º latitude D. 180º meridian

Section Check 2 2 Answer The answer is D. The International Date Line is located near the 180º meridian.

Map Projections Maps are models of Earth’s surface. Scientists use maps to locate various places and to show the distribution of various features or types of materials. Maps 3 3 For example, an Earth scientist might use a map to plot the distribution of a certain type of rock.

Map Projections A map projection is made when points and lines on a globe’s surface are transferred onto paper. All types of projections distort the shape of landmasses or their areas. Maps 3 3

Mercator Projection Mercator (mer KAY ter) projections are used mainly on ships. They project correct shapes of continents, but the areas are distorted. Maps 3 3 Lines of longitude are projected onto the map parallel to each other. When longitude lines are projected as parallel, areas near the poles appear bigger than they are.

Robinson Projection A Robinson projection shows accurate continent shapes and more accurate land areas. Maps 3 3 A Robinson projection shows accurate continent shapes and more accurate land areas.

Conic Projection Conic projections often are used to produce maps of small areas. These maps are well suited for middle latitude regions. Maps 3 3

Conic Projection Conic projections are made by projecting points and lines from a globe onto a cone. Maps 3 3 Click image to view movie.

Topographic Maps A topographic map models the changes in elevation of Earth’s surface. Maps 3 3 With such a map, you can determine your location relative to identifiable natural features. Topographic maps also indicate cultural features such as roads, cities, dams, and other structures built by people.

Contour Lines A contour line is a line on a map that connects points of equal elevation. Maps 3 3 The difference in elevation between two side-by-side contour lines is called contour interval.

Contour Lines In mountainous areas, the contour lines are close together. Maps 3 3 However, if the change in elevation is slight, the contour lines will be far apart. Some contour lines, called index contours, are marked with their elevation.

Map Scale The map scale is the relationship between the distances on the map and distances on Earth’s surface. Maps 3 3 Scale often is represented as a ratio. A map scale also can be shown in the form of a small bar that is divided into sections and scaled down to match real distances on Earth.

Map Legend A map legend explains what the symbols used on the map mean. Maps 3 3 Map Series A map series includes maps that have the same dimensions of latitude and longitude.

Geologic Maps Geologic maps show the arrangement and types of rocks at Earth’s surface. Maps 3 3 Using geologic maps and data collected from rock exposures, a geologist can infer how rock layers might have looked below Earth’s surface.

Geologic Maps The block diagram is a 3-D model that illustrates a solid section of Earth. Maps 3 3 The top surface of the block is the geologic map. Side views of the block are called cross sections, which are derived from the surface map.

Three-Dimensional Maps To visualize Earth three dimensionally, scientists often rely on computers. Maps 3 3 Pressure would increase, and the cells would become firm. Using computers, information is digitized to create a three-dimensional view of features such as rock layers or river systems. Digitizing is a process by which points are plotted on a coordinate grid.

Map Uses If you wanted to determine New Zealand’s location relative to Canada, you probably would examine a Mercator projection. Maps 3 3 If you wanted to travel across the country, you would rely on a road map, or conic projection. To climb the highest peak in your region, you would take along a topographic map.

Remote Sensing Remote sensing is a way of collecting information about Earth from a distance, often using satellites. Maps 3 3

Landsat One way the Earth’s surface has been studied is with data collected from Landsat satellites. Maps 3 3 These satellites take pictures of Earth’s surface using different wavelengths of light. The images can be used to make maps of snow cover over the United States or to evaluate the impact of forest fires.

Global Positioning System The Global Positioning System, or GPS, is satellite-based, radio-navigation system that allows users to determine their exact location anywhere on Earth. Maps 3 3 GPS technology is used to navigate, to create detailed maps, and to track wildlife.

Section Check 3 3 Question 1 Which type of map projection has parallel lines of longitude? A. conic B. Mercator C. Robinson D. topographic NC: 5.05

Section Check 3 3 Answer The answer is B. As a result of the parallel lines of longitude, areas near the poles appear bigger than they are on Mercator projections. NC: 5.05

Section Check 3 3 Question 2 A line on a map that connects points of equal elevation is called a __________ line. A. conic B. contour C. latitude D. longitude NC: 5.05

Section Check 3 3 Answer The answer is B. Contour lines that are marked with their elevations are called index contours. NC: 5.05

Section Check 3 3 Question 3 Which type of map projection would be best for mapping a polar region? A. conic B. index C. Mercator D. Robinson NC: 5.05

Section Check 3 3 Answer The answer is D. Robinson projections produce the least distortion near the poles. NC: 5.05

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